Process for forming a continuous tone negative and positive image

ABSTRACT

HIS INVETION IS DIRECTED TOWARD FORMING A SILVERLESS CONTINUOUS TONE PHOTOGRAPHIC IMAGE HAVING A SCALE INDEX BETWEEN 0.5 AND 1.5 AND A GAMMA OF 0.5-1.5 (SEE &#34;KODAK NOTES ON PRACTICAL DENSITOMETRY,&#34; PAMPHLET NO. E59, PAGES 1-76, EASTMAN KODAK COMPANY, ROCHESTER, N.Y., FOR DEFINITIONS) FROM A SUPPORTED PIGMENT OR DYE FILLED LIQUID PHOTOSENSITIVE COMPOSITION BY SELECTIVELY INSOLUBILIZING PORTIONS OF THE COMPOSITION ON EXPOSURE TO ACTINIC RADIATION AND REMOVING THE UNEXPOSED LIQUID PORTION OF HE COMPOSITION FROM THE SUPPORT.

United States Patent 3,726,676 PROCESS FOR FORMING A CONTINUOUS TONENEGATIVE AND POSITIVE IMAGE Arthur Donald Ketley, Columbia, CliftonLeroy Kehr, Silver Spring, and Jennie Lee Touchette, Columbia, Md.,assignors to W. R. Grace & Co., New York, N.Y.

No Drawing. Original application Oct. 11, 1968, Ser. No. 766,948.Divided and this application July 15, 1971, Ser. No. 163,081

Int. Cl. G03c 5/08 US. Cl. 96-27 17 Claims ABSTRACT OF THE DISCLOSUREThis invention is directed toward forming a silverless continuous tonephotographic image having a scale index between 0.5 and 1.5 and a gammaof 0.5-1.5 (see Kodak Notes on Practical Densitometry, Pamphlet No. E59,pages 1-76, Eastman Kodak Company, Rochester, N.Y., for definitions)from a supported pigment or dye filled liquid photosensitive compositionby selectively insolubilizing portions of the composition on exposure toactinic radiation and removing the unexposed liquid portion of thecomposition from the support.

This application is a divisional application of our copendingapplication having Ser. No. 766,948, filed Oct. 11, 1968 now US. Pat.3,623,879.

Continuous tone photographic materials used today consist of silverhalide emulsions coated on supports, the silver halide being convertedto metallic silver by the action of light and a developer. The systemhas several disadvantages. One disadvantage is the skyrocketing cost ofsilver due to silver being in such short supply. Another drawback isthat all work must be done in the dark, thus necessitating costlydarkrooms. Our materials do not employ silver and do not requireexpensive, inconvenient darkrooms as they are sensitive only to UVlight. Also, conventional photographic. printing materials are coated onpaper since the support has to be permeable to the aqueous solution ofdeveloper. In our process the image is formed on a transparent supportthat can then be laminated to any kind of backing-cloth, wood, plastic,metal, et cetera, to give a wide variety of effects.

Recently Du Pont has marketed Crolux, a photopolymerizable compositionthat yield images on exposure to light. Crolux, however, gives onlyblack and white images and no intermediate gray tones and thus is notadaptable to use as a photographic print medium.

One object of this invention is to prepare a material giving acontinuous tone photographic image having a scale index between 0.5 and1.5 and a gamma of 0.5-1.5.

Another object of the instant invention is to prepare such materialwithout use of silver.

A third object is to prepare such a material that can be processed innormal room lighting.

Yet another object of the present invention is to prepare a photographicfilm and print material giving an image quality superior to any knownnon-silver system.

Another object is to prepare printing materials having difierentcontrast ranges so that they will give good prints from both hard andsoft negatives.

Still another object of the invention is to provide a new, simpletechnique for preparing color prints from color separation negatives.

A further object is to provide a means of producing large continuoustone transparencies for use in overhead projectors.

A still further object of the invention is to provide a low cost simplemeans of reproducing microfilm.

3,726,676 Patented Apr. 10, 1973 Summarily, it has been found thatphotographic images can be prepared by sandwiching a layer adjusted to auniform thickness in the range 0.3-50 mils of a pigment or dye filledliquid photosensitive composition having a viscosity in the range 0' to20 million centipoises at 70 C. and a photosensitizer or curing rateaccelerator between two films at least one of which transmits actinicradiation, exposing said composition to actinic radiation through animage-bearing, continuous tone transparency maintained adjacent to andpreferably in contact with the transparent support film of the laminateand substantially parallel to the layer of said composition wherebyportions of the composition exposed to actinic radiation on thetransparent support film proximate the actinic radiation source react tobecome solidified to form an image and portions of said composition onthe opposite film away from the actinic radiation source, react tobecome solidified to form a reverse image, separating said films andremoving the unpolymerized liquid photosensitive composition therefromthus forming a continuous tone positive and negative image, saidpositive image being laminated to a background material, eg, a highreflectance material, such as white pigmented polyvinyl chloride to givea continuous tone photographic print.

As used herein the term liquid photosensitive composition means a liquidcomposition having a viscosity in the range 0 to 20 million centipoisesat 70 C. which is solidified either by photocuring orphotopolymerization or both on exposure to actinic light.

One photosensitive system which is suitable for use in the instantinvention is that set out in a copending application having U.S. Ser.No. 674,773, now abandoned, filed Oct. 12, 1967 assigned to the sameassignee and incorporated by reference herein. In said system a printingplate is formed from a layer of a UN. photoourable compositionconsisting of a 2 to 98 parts by 'weight of a polyene containing atleast two unsaturated carbon to carbon bonds per molecule, 98 to 2 partsby weight of a polythiol containing two or more thiol groups permolecule and a photocuring rate accelerator, i.e., a photosensitizer,e.g. benzophenone, said layer preferably being adhered to a support.

As used therein polyenes and polynes refer to a simple or complexspecies of alkenes or alkynes having a multiplicity, i.e., at least 2,reactive carbon to carbon unsaturated functional groups per averagemolecule. For example, a diene is a polyene that has two reactive carbonto carbon double bonds per average molecule, while a diyne is a polyynethat contains in its structure two reactive carbon to carbon triplebonds per average molecule. Combinations of reactive double bonds andreactive triple bonds Within the same molecule are also operable. Anexample of this is monovinylacetylene, which is a polyeneyne under ourdefinition. For purposes of brevity all these classes of compounds willbe referred to herein as polyenes.

As used herein the term reactive unsaturated carbon to carbon groupsmeans groups which will react under proper conditions as set forthherein with thiol groups to yield the thioether linkage as contrasted tothe term unreactive carbon to carbon unsaturation which means groupswhen found in aromatic nucleii (cyclic structures exemplified bybenzene, pyridine, anthracene, tropolone and the like) which do notunder the same conditions react with thiols to give thioether linkages.In the instant invention, products from the reaction of polyenes withpolythiols which contain 2 or more thiol groups per average molecule arecalled polythioether polymers or polythioethers.

One group of polyenes operable in the instant invention to react withpolythiols to form a photographic medium is that taught in a copendingapplication having Ser. No. 617,801 filed Feb. 23, 1967, now abandoned,assigned to the same assignee and incorporated herein by reference. Thisgroup includes those having a molecular weight in the range 50 to20,000, a viscosity ranging from O to 20 million centipoises at 70 C. ofthe general formula: [A-HX) wherein X is a member of the groupconsisting of R R Bikeand RCEC; m is at least 2; lected from the groupconsisting of hydrogen, halogen, aryl, substituted aryl, cycloalkyl,substituted cycloalkyl, aralkyl, substituted aralkyl and alkyl andsubstituted alkyl groups containing 1 to 16 carbon atoms and A is apolyvalent organic moiety free of (1) reactive carbon to carbonunsaturation and (2) unsaturated groups in conjugation with the reactiveene or yne groups in X. Thus A may contain cyclic groupings and minoramounts of hetero atoms such as N, S, P or but contains primarilycarboncarbon, carbon-oxygen or silicon-oxygen chain linkages without anyreactive carbon to carbon unsaturation.

Examples of operable polyenes from this group include, but are notlimited to l) Crotyl-terminated polyurethanes which contain two reactivedouble bonds per average molecule in a near terminal position of theaverage general formula:

R is independently sewherein x is at least 1,

(2) The following structure which contains terminal reactive doublebonds:

H II CHz CI"I-CH2NHC OGiBB x0- blb where x is at least 1,

(3) The following structure which contains terminal reactive doublebonds:

where x is at least 1, and

as polyisoprene, polybutadiene, styrene-butadiene rubber,isobutylene-isoprene rubber, polychloroprene,styrenebutadiene-acrylonitrile rubber and the like; unsaturatedpolyesters, polyamides, and polyurethanes derived from monomerscontaining reactive unsaturation, e.g. adipic acid-butenediol,1,6-hexanediamine-fumaric acid and 2, 4-tolyler1ediisocyanate-butenediol condensation polymers and the like.

A third group of polyenes operable in this invention includes thosepolyenes in which the reactive unsaturated carbon to carbon bonds areconjugated with adjacent unsaturated groupings. Examples of operablereactive conjugated ene systems include, but are not limited to, thefollowing:

A few typical examples of polymeric polyenes which contain conjugatedreactive double bond groupings such as those described above arepolyethyleneether glycol diacrylate having a molecular weight of about750, polytetramethyleneether glycol dimethacrylate having a molecularweight of about 1175, the triacrylate of the reaction product oftrimethylolpropane with 20 moles of ethylene oxide, and the like.

Included in the term polyenes as used herein are those materials whichin the presence of an inert solvent, aqueous dispersion or plasticizerfall within the viscosity range set out above at 70 C.

As used herein, the term polythiols refers to simple or complex organiccompounds having a multiplicity, i.e. at least 2, of pendant orterminally positioned SH functional groups per average molecule.

On the average the polythiols must contain 2 or more SH groups/molecule.They usually have a viscosity range of 0 to 20 million centipoises(cps.) at 70 C. as

measured by a Brookfield viscometer. Included in the term polythiols asused herein are those materials which in the presence of an inertsolvent, aqueous dispersion of plasticizer fall within the viscosityrange set out above at 70 C. Operable polythiols in the instantinvention usually have molecular weights in the range 20,000, preferably10o 10,o00.

The polythiols operable in the instant invention can be exemplified bythe general formula: R -(SH) where n is at least 2 and R is a polyvalentorganic moiety free from reactive carbon to carbon unsaturation. Thus R(4) The following structure which contains near termay contain cyclicgroupings and minor amounts of hetero atoms such as N, S, P or 0 butprimarily contains carminal reactive double bonds:

r H CH CH: CH CH-CH os( )7- z 7 where x is at least 1.

A second group of polyenes operable in the instant invention includesunsaturated polymers in which the double or triple bonds occur primarilywithin the main chain of the molecules. Examples includes conventionalelastomers bon-hydrogen, carbon-oxygen, or silicon-oxygen containingchain linkages free of any reactive carbon to carbon unsaturation.

One class of polythiols operable with polyenes in the instant inventionto obtain an essentially odorless cured (derived primarily from standarddiene monomers) such polythioether photographic medium are esters ofthiolcontaining acids of the general formula: HS'R COOH where R is anorganic moiety containing no reactive carbon to carbon unsaturation withpolyhydroxy compounds of the general structure: R (OH) where R is anorganic moiety containing no reactive carbon to carbon unsaturation andn is 2 or greater. These components will react under suitable conditionsto give a polythiol having the general structure:

where R and R are organic moieties containing no reactive carbon tocarbon unsaturation and n is 2 or greater.

Certain polythiols such as the aliphatic monomeric polythiols (ethanedithiol, hexamethylene dithiol, deca methylene dithiol,tolylene-2,4-dithiol, etc.) and some polymeric polythiols such as athiol-terminated ethylcyclohexyl dimercaptan polymer, etc. and similarpolythiols which are conveniently and ordinarily synthesized on acommercial basis although having obnoxious odors, are operable in thisinvention. Examples of the polythiol compounds preferred for thisinvention because of their relatively low odor level and fast curingrate include but are not limited to esters of thioglycolic acid(HS-CHzCOOH) ot-mercaptopropionic acid (HS-CH(CH )COOH) and omercaptopropionic acid (HSCH CH COOH) with polyhydroxy compounds such asglycols, triols, tetraols, pentaols, hexaols, etc. Specific examples ofthe preferred polythiols include but are not limited to ethylene glycolbis (thio glycolate), ethylene glycol bis '(fi-mercaptopropionate),trimethylolpropane tris (thioglycolate), trimethylolpropane tris(B-mercaptopropionate), pentaerythritol tetrakis (thioglycolate) andpentaerythritol tetrakis (B-mercaptopropionate), all of which arecommercially available. A specific example of a preferred polymericpolythiol is polypropylene ether glycol bis (B-mercaptopropionate) whichis prepared from polyproyleneether glycol (e.g. Pluracol P2010,Wyandotte Chemical Corp.) and fi-mercaptopropionic acid byesterification.

The preferred polythiol compounds are characterized by a low level ofmercaptan-like odor initially, and after reaction, give essentiallyodorless cured polythioether end products which are commercially usefulresins or elastomers for a photographic medium.

As used herein the term odorless means the substantial absence of theWell known offensive and sometimes obnoxious odors that arecharacteristic of hydrogen sulfide and the derivative family ofcompounds known as mercaptans.

The term functionality as used herein refers to the average number ofene or thiol groups per molecule in the polyene or polythiol,respectively. For example, a triene is a polyene with an average ofthree reactive carbon to carbon unsaturated groups per molecule and thushas a functionality (f) of three. A dithiol is a polythiol with anaverage of two thiol groups per molecule and thus has a functionality(f) of two.

It is further understood and implied in the above definitions that inthese systems, the functionality of the polyene and the polythiolcomponent is commonly expressed in whole numbers although in practicethe actual functionality may be fractional. For example, a polyenecomponent having a nominal functionality of 2 (from theoreticalconsiderations alone) may in fact have an effective functionality ofsomewhat less than 2. In an attempted synthesis of a diene from a glycolin which the reaction proceeds to 100% of the theoretical value forcomplete reaction, the functionality (assuming 100% pure startingmaterials) would be 2.0. If, however, the reaction were carried to only95% of theory for complete reaction, about 10% of the molecules presentwould have only one ene functional group, and there may be a trace ofmaterial that would have no ene functional groups at all. Approximatelyof the molecules, however, would have the desired diene structure andthe product as a whole then would have an actual functionality of 1.9.Such a product is useful in the instant invention and is referred toherein as having a functionality of 2.

The aforesaid polyenes and polythiols can, if desired, be formed orgenerated in situ and still fall within the scope of the instantinvention.

To obtain the maximum strength, solvent resistance, creep resistance,heat resistance and freedom from tackiness, the reaction componentsconsisting of the polyenes and polythiols of this invention areformulated in such a manner as to give solid, crosslinked, threedimensional network polythioether polymer systems on curing. In order toachieve such infinite network formation, the individual polyenes andpolythiols must each have a functionality of at least 2 and the sum ofthe functionalities of the polyene and polythiol components must alwaysbe greater than 4. Blends and mixtures of the polyenes and thepolythiols containing said functionality are also operable herein.

In general, it is preferred, especially at or near the operable lowerlimits of functionality in the polyene and polythiol, to use thepolythiol and the polyene compounds in such amounts that there is onethiol group present for each ene group, it being understood that thetotal functionality of the system must be greater than four, and thefunctionality of the thiol and the diene must each be at least two. Forexample, if two moles of a triene are used, and a dithiol is used as thecuring agent, making the total functionality have a value of five, it ispreferable to use three moles of the dithiol. If much less than thisamount of the thiol is used, the curing rate will be lower and theproduct will be weaker in some respects because of the reduced crosslinkdensity. If much more than the stoichiometric amount of the thiol isused, the rate of cure may be higher, if that is desirable, althoughexcessive amounts can lead to a plasticized crosslinked product whichmay not have the desired properties. However, it is within the scope ofthis invention to adjust the relative amounts of polyenes and polythiolsto any values above the minimum scope disclosed herein which givedesirable properties to the crosslinked polythioether. It must beemphasized that regardless of the ratio of polythiol to polyene, thetotal functionality of the system must be greater than four, or acrosslinked network will not result, and the product will be aswellable, chainextended composition which is unsuitable for the purposeof this invention. Thus in practicing the instant invention to obtain asolid crosslinked photographic medium, it is necessary to use a polyenecontaining at least 2 unsaturated carbon to carbon bonds per molecule inan amount that the combined functionality of the unsaturated carbon tocarbon bonds per molecule of polyene and the thiol groups per moleculeof polythiol is greater than 4.

The above systems are preferred. However, any system having an initialviscosity in the range 0-20 million centipoises at 70 C. which can befilled with pigment or dye and then either photopolymerized, photocuredor both to a solid polymer from which the unpolymerized material may bestripped by washing or other means is operable.

In the case of polyenes which are to be photopolymerized, it ispreferable not to have a polythiol present in the composition, butrather to have only the one monomer (usually a conjugated ene monomerwhich is commonly known as an addition polymerizable vinyl monomer) anda photoinitiator as the reactive components of the photopolymerizablecomposition. See U.S. 2,760,- 863; 3,380,831, etc. for examples of someof these kinds of systems.

The liquid photosensitive compositions to be converted to solidphotographic material, in accord with the present invention may, ifdesired, include such additives as antioxidants, accelerators, dyes,inhibitors, activators, fillers, pagments, antistatic agents,flame-retardant agents, thickeners, thixotropic agents, surface-activeagents, light scattering agents, viscosity modifiers, extending oils,plasticizers, tackifiers and the like within the scope of thisinvention. Such additives are usually preblended with the monomer orcompound to be photosensitized or with the polyene or polythiol prior toor during the compounding step. Such fillers, however, unless they areused for the purpose of pigmenting or dying the image, should not besubstantially opaque when present in the photosensitizable polymer. Theaforesaid additives may be present in quantities up to 500 parts or moreper 100 parts of the liquid photosensitive composition by Weight andpref erably 0.005-300 parts on the same basis, but each additive must bepresent in an amount which will not interfere with or inhibit thenecessary photocuring or photopolymerization image-producing reaction orother required steps in the photographic process.

The colors of the continuous tone prints obtained by the practice of theinstant invention can be of infinite variety. For example, it onedesired a red and yellow print, a red pigment is included in thephotosensitive composition and the resultant photosensitized image islaminated to a piece of high reflectance yellow paper to give asilverless, red and yellow continuous tone photographic print. By thesame token, a yellow pigment can be employed and the photosensitizedimage can be laminated to a piece of high reflectance red paper.

For black and white prints, carbon blacks conventionally used for inks,plastics, rubbers, etc; may be employed as pigments. These include theso-called channel, furnace and thermal blacks having particle diametersof -250 millimicrons. Black dyes which are generally azine and azoorganic compounds are also operable.

For colored prints any suitably colored dye is operable that does notcontain groups which would inhibit the polymerization or curing systemused.

The support to which the photosensitive composition is adhered can beformed from various materials such as plastic, glass, quartz, and thelike. The support is preferably a plastic having the characteristics ofbeing flexible, adherable to the photosensitive composition on exposureto U.V. radiation or by other means and can transmit a substantialamount of U.V. light. The thickness of the support is dependent on itsrelative strength and dimensional stability to hold a specifiedthickness of the photosensitive composition and can be empiricallydetermined by one skilled in the art. For example when an orientedpolyethylene terephthalate in film form sold under the trade name Mylaris employed as the support, the Mylar film will usually have a thicknessof about 0.5 to mils.

The photosensitive reaction can be initiated by actinic radiation fromsunlight or from special light sources which emit significant amounts ofactinic light suitably in the wavelength range of 2200-4000 A. Thus, itis possible merely to expose the liquid photosensitive compositionthrough the transparent support film to actinic radiation preferably inthe range 2200-4000 A. under ambient conditions or otherwise and obtaina solid elastomeric or resinous product useful as a photographicmaterial after development.

The photosensitive reaction rate can be increased by the use of aphotosensitizer. As used herein a photosensitizer means either aphotoinitiator as employed in a polymerization reaction or a curing rateaccelerator as used in a curing reaction or both. For examplebenzophenone when added to a liquid photopolymerizable composition suchas monomeric pentaerythritol triacrylate would be a photoinitiatorwhereas benzophenone would be a curing rate accelerator for the liquidphotocurable composition comprised of a polyene and a polythiol.

Various photosensitizers are operable and well known to those skilled inthe art. Examples of photosensitizers include, but are not limited to,benzophenone, acetophenone, acenapthene-quinone, methyl ethyl ketone,valerophenone, hexanophenone, 'y-phenylbutyrophenone, pmorpholinopropiophenone, dibenzosuberone, 4 morpholinobenzophenone,'-morpholinodeoxybenzoin, p-diacetylbenzene, 4-aminobenzophenone,4'-methoxyacetophenone, benzaldehyde, oz tetralone, 9acetylphenanthrene, 2-acetylphenanthrene, l0-thioxanthenone,3-acetylphenanthrene, 3-acetylindole, 9-fluoroenone, l-indanone,1,3,5-triacetylbenzene, thioxanthen-9-one, xanthene-9-one,7-H-benz[de]anthracen-7-one, 1 naphthaldehyde, 4,4- bis(dimethylamino)benzophenone, fluorene-Q-one, 1'- acetonaphthone, 2'-acetonaphthone and2,3-butanedione, etc. which serve to give greatly reduced exposure timesand thereby when used in conjunction with various forms of energeticradiation yield very rapid, commercially practical time cycles by thepractice of the instant invention. The photosensitizers, i.e. curingrate accelerators or photoinitiators are usually added in an amountranging from 0.0005 to 50% by weight, preferably 0.5 to 25%, of thephotocurable or photopolymerizable composition in the instant invention.Such photosensitizers are also useful in that they control the contrastor gamma of the resulting image so that at low concentrations highcontrast is obtained while at high concentrations low contrast isobtained. Hence photographic printing materials can be prepared that areequivalent to the grades of silver-based printing papers and can bematched to negatives of varying contrast.

The compounding of the components of the liquid photosensitivecomposition prior to exposure to U.V. radiation can be carried out inseveral ways. For example, in the case of the liquid photocurablecomposition, the polyene, the polythiol and any other additives, e.g.,photosensitizer pigment or dye are admixed in an inert atmosphere andcharged to an aerosol can, drum, tube, or cartridge for subsequent use.Exposure of said admixed components to actinic radiation under ambientor elevated temperature conditions will initiate photocuring.

Another useful method of compounding the photocurable composition is toprepare by conventional mixing techniques but in the absence of actinicradiation a composition consisting of polyene, antioxidant (to inhibitspontaneous oxygen-initiated curing), polythiol, pigment, U.V.sensitizer or photoinitiator, and other inert additives. Thiscomposition generally can be stored in closed containers in the dark forextended periods of time, but on exposure to actinic radiation (e.g.,ultraviolet light, sunlight, etc.) will cure controllably and in a veryshort time period to solid polythioether photographic products.

Conventional curing inhibitors or retarders operable with thephotocurable compositions in the instant invention include but are notlimited to hydroquinone; p-tertbutyl catechol;2,6-ditertbutyl-p-methylphenol; phenothiazine andN-phenyl-Z-naphthylamine.

The molecular weight of the polyenes of the instant invention can bemeasured by various conventional methods including solution viscosity,osmotic pressure and gel permeation chromatography. Additionally, themolecular weight can he sometimes calculated from the known molecularweight of the reactants.

The viscosity of the polyenes and polythiols was measured on aBrookfield Viscometer at 30 or 70 C. in accord with the instructionstherefor.

I mer and intermediate densities to intermediate thicknesses of polymer.The inverse correspondence between the density of the negative and thethickness (and hence opacity) of the filled photosensitive polymerresults in the conversion of a continuous tone negative to a continuoustone print. Likewise, if the material is used in a camera, a continuoustone scene will be rendered as a continuous tone negative. Continuoustone separation negatives will likewise yield continuous tonetransparencies from polymer films dyed with the complementary colors tothe filters used to prepare the negatives. When these are superimposed,a continuous tone, full color print results.

The photosensitive material can be exposed to U.V. through a negativethat is in contact with the support, or the negative image can beprojected onto the support or the material can be placed in a camerawith the support towards the lens and exposed like a conventionalphotographic film. The photosensitive polymer layer can be sandwichedbetween the transparent support and another film layer of variouscompositions, e.g. metal, paper, plastic etc. in which case the laminatecan easily be handled in conventional photographic equipment such ascameras, enlargers, contact printing frames, etc. However, exposure canbe made without this additional film layer by keeping the support level,e.g., with the photopolymer on top, and exposing to U.V. through thesupport from underneath the support. The development of the exposed filmis carried out by immersing it in an aqueous solution containing a soapor detergent or a solvent, preferably alcohol and depending on the soapor detergent or solvent, is etched for periods ranging from seconds upto one hour or more followed by blotting with a sponge and drying by acurrent of air or by radiant heat. However, for some of thephotosensitive compositions the resulting image contains minorimperfections even when etched for extended periods in conjunction withmechanical means. It has now been found that using an aqueous solutionof detergent or soap or a solvent in combination with ultrasonicactivation of the bath to impart cavitation thereto, the etching timecan be reduced to periods of 1 second to minutes without enlistingmechanical aids such as brushes, sponges, etc. and the image obtained isfar superior in quality and in fidelity of image reproduction to thatpreviously obtained using photopolymerizable or photocurable materialsand as good as that obtained using silver films.

The greater the difference in solubility between the solidified areas inthe photosensitized plate and portions of said plate which remainliquid, the greater the efliciency of the process to make the image.Thus, it is important in the instant invention to select the rightdetergent, soap or solvent in the etching bath to facilitate removal.

A convenient method of carrying out the process of this invention is toplace an image bearing positive or negative continuous tone transparencyin a contact frame or enlarger parallel to the surface of a layer of apigment or dye filled photosensitive composition, i.e. photocurable orphotopolymerizable composition or both which has been cast directly on atransparent support and adjusted for uniformity of height by suitablemeans, e.g. a drawbar, precast mold and the like. The layer of thephotosensitive composition can be covered with a film layer to form asandwich, if desired. The layer of the photosensitive composition isexposed through the transparency and the transparent support to a sourceof actinic light suitably in the wavelength range of 2200-4000 A., untilthe 10 layer is cured or polymerized or both to an insoluble stage inthe exposed areas.

If the photosensitive composition is sandwiched between the transparentsupport layer and another layer, then the two layers are pulled apartleaving, on the transparent support, a cured reverse image of thetransparency and uncured polymer. The transparent support hearing thereverse image is then developed by removing uncured polymer with anappropriate solvent. The photographic transparency is thereafter driedin air or in an oven at elevated temperatures up to about 150 C.Furthermore, if desired, the thus formed image can be further subjectedto U.V. radiation for periods up to 10 minutes to further harden it.

The resulting image on its transparent support or backing may be furtherprocessed in a number of ways:

(1) If it is a negative made in a camera it may be used directly to makeprints by any conventional process or by the process described inExample 10 below.

(2) If the transparency is a positive, it may be coated with anytransparent adhesive or with a transparent photosensitive polymer laiddown upon any white reflecting material to give a black and white printand reexposed to U.V. radiation for adhesion. Ordinary transparentadhesives are also operable and do not require U.V. reexposure. Colorprints of three or more separation positives can be made in the samemanner. Various tones may be obtained by varying the color cast of thesupport. Preferred backings are paper, white vinyl and any other whitepigmented plastic.

(3) If a transparency for projection is desired, the image can beprojected as is but preferably is laminated to another sheet of clear,transparent plastic to prevent possible handling damage to the imagematerial.

The following examples will aid in explaining, but should not be deemedas limiting, the instant invention. In all cases unless otherwise noted,all parts and percentages are by weight.

EXAMPLE 1 Formation of polyene polymer To a 2 liter flask equipped withstirrer, thermometer and gas inlet and outlet was charged 450 g. (0.45mole) of polytetramethylene ether glycol, having a hydroxyl number of112 and a molecular weight of approximately 1,000, along with 900 g.(0.45 mole) of polytetramethylene ether glycol having a hydroxyl numberof 56 and a molecular weight of about 2,000, both commercially availablefrom Quaker Oats Co. The flask was heated to C. under vacuum andnitrogen and maintained thereat for 1 hour. The flask was then cooled toapproximately 70 C. whereat 0.1 g. of dibutyl tin dilaurate was added tothe flask. A mixture of 78 g. (0.45 mole) of tolylene diisocyanate and78 g. (0.92 mole) of allyl isocyanate was thereafter added to the flaskdropwise with continuous stirring. The reaction was maintained at 70 C.for 1 hour after addition of all the reactants. The thus formed allylterminated polymer will hereinafter be referred to as Polymer A.

EXAMPLE 2 10 g. of Polymer A, 0.9 g. of pentaerythritol tetrakis(B-mercaptopropionate) and 1.5 g. carbon black (Sterling FT) in ethyleneglycol monoethyl ether were mixed together and then heated in a vacuumoven for 5 minutes at C. 0.15 g. of benzophenone was then added andmixed for 2 minutes. A 1 mil film of this material was spread on a sheetof opaque Mylar and a 1.0 mil thick sheet of clear Mylar rolled on topto produce a sandwich. The sandwich (clear side up) was exposed under acontinuous tone photographic negative to a 275 watt U.V. lamp 9" awayfor 3 minutes. Upon peeling the sandwich apart, a negative image, i.e.one identical to the photographic negative through which the lightpassed,

1 1 adhered to the opaque Mylar and a positive continuous tone image,i.e. reversed relative to the negative through which the light passedwas formed on the clear Mylar. Uncured polymer was removed from both thepositive and negative images by blotting with paper soaked in ethanol.The positive image was then dried and laminated to a piece of highreflectance white paper to give a silverless, black and white continuoustone photographic print. The visual appearance and quality of thephotocured polymer print obtained in the above manner was such that itcould not be dilferentiated from a standard silver halide print madefrom the same negative using conventional printing technology.

EXAMPLE 3 The procedure and reactants of Example 3 were employed exceptthat the clear sheet was oriented polystyrene instead of clear Mylar.

EXAMPLE 5 The procedure and reactants of Example 4 were employed exceptthat a polycarbonate film was used for the clear sheet.

EXAMPLE 6 The procedure and reactants of Example 3 were employed exceptthat Sterling FT carbon black was replaced by 1.0 g. of a black dye,i.e. Aquaprint 055207 Black K from Interchemical Co.

EXAMPLE 7 The procedure and reactants of Example 3 were employed exceptthat 4.3% benzophenone based on the weight of photosensitive compositionwas used and the exposure time was 1 minute. A lower contrast print wasobtained.

EXAMPLE 8 The procedure and reactants of Example 3 were employed exceptthat benzophenone based on the weight of photosensitive composition wasused and a 0.2 minute exposure was employed. A Very low contrast printwas obtained.

EXAMPLE 9 A Kodak calibrated 21 step density wedge was exposed using thematerial of Example 7. The resulting image was used to generate acharacteristic curve using a Kodak Densitometer. 16 steps were measured,the density of which, when plotted vs. log exposure gave a gamma of 1.2.This is equivalent to a medium speed silver emulsion film such asPanatomic X developed in a fine grain developer.

EXAMPLE 10 A sandwich of the photosensitive material of Example 8 wascut to 5" X 4 and the edges sealed by brief exposure to UV. light. Thefilm so obtained was loaded into Graphic cut film holders, transparentside nearest the lens. Exposures were made in a Polaroid MP 4 Technicalcamera fitted with a Goerz Dagor lens. Illumination of the subject (awatch lying on a 3 color picture as background) was supplied by two 275watt sun lamps.

Exposures were 10-15 minutes at f4.5. A measurement of ASA rating forthis film was made by measuring, with an exposure meter, what theexposure would have been with an ASA film and then extrapolating backfrom the actual exposure. The ASA rating calculated in this Way was0.01.

The silverless photographic negative obtained as above was printed togive an excellent continuous tone silverless,

black and white print using the procedure of Example 3.-

This example illustrates the formation of a photographic print in whichthe entire operation is carried out Without the use of silver halidetechnology.

EXAMPLE 11 Using conventional silver halide film, three separationnegatives were prepared by photographing a scene with a NationalOne-Shot Camera. The negatives were prepared through the followingfilters: Wratten #25 (red), Wratten #58 (green) and Wratten #47 (blue).

The negative prepared through the red filter was printed using theprocedure of Example 3 except that carbon black was replaced by 3.5 g.of Adpro blue dye.

The negative prepared through the green filter was printed using theprocedure of Example 3 except that carbon black was replaced by 3.5 g.of Adpro yellow dye.

The negative prepared through the blue filter was printed using theprocedure of Example 3 except that carbon black was replaced by 3.5 g.of Adpro red dye.

The three colored images were then superimposed and laminated to a whitevinyl base to give an excellent silverless photographic three colorprint.

EXAMPLE 12 The reactants and procedures of Example 11 were used exceptthat the three colored images were then superimposed and laminated to apiece of clear Mylar to give a three color transparency.

EXAMPLE 13 Example 2 was repeated except that Polymer A was replaced by10 g. of a poly (1,3-butadiene) of approximately 2000 molecular weightand benzene was used as the washing solvent instead of ethanol. Theresults were essentially the same.

EXAMPLE 14 The procedure of Example 2 was repeated except that Polymer Awas replaced with 2.7 g. of the triacrylate of the reaction product oftrimethylol propane with 20 moles of ethylene oxide. The results wereessentially the same in yielding a continuous tone black and whitephotographic print.

EXAMPLE 15 15 g. of DION Polymercaptan Resin DPM-lOO commerciallyavailable from Diamond Alkali Co. having a thiol functionality of 2 to 3and a molecular Weight of about 5,000, 0.36 g. triallyl urea and 1.0 g.carbon black (Sterling FT) in ethylene glycol monoethyl ether were mixedtogether and then heated in a vacuum oven for 5 minutes at C. 1.0 g. ofbenzophenone was then added and mixing was continued for 2 minutes. A 1mil film of this mixture was spread on a sheet of opaque Mylar and asheet of clear Mylar was rolled on top of the mixture to produce asandwich. The sandwich (clear side up) was exposed under a continuoustone, photographic negative to a 275 watt U.V. lamp situated 9" away for3 minutes. Upon peeling the sandwich apart, a negative image, i.e. oneidentical to the photographic negative through which the light passed,adhered to the opaque Mylar and a positive continuous tone image, i.e.reversed relative to the negative through which the light passed, formedon the clear Mylar. Uncured polymer was removed from the images byblotting with paper soaked in ethanol. The positive image was then driedand laminated to a piece of high reflectance paper to produce asilverless, black and white, continuous tone, photographic print. Thevisual appearance of the thus produced print could not be dilferentiatedfrom a standard silver halide print using the same negative andconventional printing technology.

EXAMPLE 17 Example 2 was repeated except that 18 g. of DIONPolymercaptan Resin DPM-l002" was substituted for the 0.9 g. ofpentaerythritol tetrakis (fl-mercaptopropionate). A good silverless,continuous tone, photographic print reresulted which could not bedifierentiated from the standard silver halide print made from the samenegative using conventional printing technology.

EXAMPLE 18 Example 9 was repeated except that Polymer A was replaced by3.8 g. of triallyl urea, 9.8 g. of pentaerythritol tetrakis(B-mercaptopropionate) was used and the image was developed by washingwith acetone instead of ethanol. The print of the step wedge showed 15steps and the characteristic curve gave a gamma of 1.1.

EXAMPLE 19 Example 9 was repeated except that Polymer A was replaced by6.0 g. of an allyl terminated epoxy prepolymer prepared from reactingstoichiometric amounts of diallyl amine and diglycidyl ether ofbisphenol A, commerically available from Shell Chemical Co., saidprepolymer having a molecular weight of about 616 and 5.0 g. ofpentaerythritol tetrakis (fl-mercaptopropionate) was used. Acharacteristic curve generated with a Kodak 21 step wedge consisted of15 measurable steps with a gamma of 0.92.

EXAMPLE 20 Example 2 was repeated except that Polymer A was replaced byan equal weight of cellulose acetate methacrylate. A good continuoustone photographic print was produced.

EXAMPLE 21 5 g. of DION Polymercaptan Resin DPM-l002 commerciallyavailable from Diamond Alkali Co. having a thiol functionality of 2 to 3and a molecular weight of about 5,000, 2.5 g. of triallyl cyanurate, and2.5 g. of carbon black (Sterling FT) in ethylene glycol monoethyl etherwere mixed together and then heated in a vacuum oven for minutes at 120C. 5.0 g. of benzophenone was added to the mixture and mixing wascontinued for 2 minutes. A 1 mil film of this mixture was spread on asheet of an opaque Mylar and a sheet of clear Mylar was rolled on top ofthe mixture to produce a sandwich. The thus formed sandwich, clear sideup, was exposed under a continuous tone photographic negative to a 275watt U.V. lamp situated 9" away for 3 minutes. The sandwich was thenpeeled apart resulting in a positive image, i.e. one reversed relativeto the photographic negative through which the light passed adhering tothe clear Mylar. Uncured polymer was removed from the positive image byblotting with paper soaked in ethanol. The positive continuous image wasthen dried and laminated to a piece of high reflectance white paper togive a silverless, black and white, continuous tone, photographic print.The quality 14 and appearance of the thus formed print was of the samecaliber as a standard silver halide print made from the same negativeusing conventional printing technology. This example illustrated the useof a photosensitive composition containing a monomeric polyene and apolymeric polythiol.

EXAMPLE 22 600 g. (0.22 mole) of a polypropylene ether triol having amolecular weight of 2,960 commercially available under the trade nameTriol 3000 by Union Carbide Corp. was charged to a 1 liter resin kettlealong with 0.3 g. of dibutyl tin dilaurate. The kettle was heated to C.under vacuum and maintained thereat for 1 hour. The kettle was cooled to60 C. whereat 40 g. (0.48 mole) of allyl isocyanate was added dropwisefrom a dropping funnel to the reaction mixture. After 20 minutes the NCOcontent was 0.80 mg. NCO/ g. The thus formed prepolymer was thenmaintained under vacuum at 70 C. for 1 hour followed by 2 hours at 90 C.This allyl-terminated polymer was identified as Polymer B. 50 g. ofPolymer B plus 60 g. of DION Polymercaptan Resin DPM-1002 and 5 g. ofcarbon black (Sterling FT) in ethylene glycol monoethyl ether were mixedtogether and then heated in a vacuum oven for 5 minutes at C. 5.0 g. ofbenzophenone was then added to the mixture and mixing was continued for2 minutes. A 1 mil film of this mixture was spread on a sheet of opaqueMylar and a sheet of clear Myar (1 mil thick) was rolled on top of thephoto sensitive mixture to produce a sandwich. The thus formed sandwich,clear side up, was exposed through a continuous tone photographicnegative in contact therewith to a 275 watt U.V. lamp situated 9" awayfor 3 minutes. The negative was removed and the sandwich was peeledapart resulting in a positive image, i.e. one reversed relative to thephotographic negative through which the light passed adhering to theclear Mylar while a negative image was left on the opaque Mylar. Uncuredpolymer was removed from the images by blotting with paper soaked inethanol. The positive, continuous tone image was then dried andlaminated to a piece of high reflectance white paper to give asilverless, black and white, continuous tone, photographic print. Thequality and appearance of said print could not be differentiated fromthe standard silver halide print from the same negative usingconventional printing technology.

EXAMPLE 23 24.4 g. of pentaerythritol tetra-kis (p-mercaptopropionate),25.6 g. of the reaction product of -1 mole of 1,4- butanediol with 2moles of allyl isocyanate along with 1.5 g. of carbon black (SterlingFT) in ethylene glycol monoethyl ether were mixed together and thenheated in a vacuum oven for 5 minutes at 120 C. 2.5 g. of benzophenonewere added to the mixture and mixing was continued for 1 minute. A 1 milfilm of this photosensitive mixture was spread onto a U.V. transparentMylar" zfilm (5 mil thick) and a 1 mil thick U.V. transparent Mylar filmwas rolled on top of the mixture to produce a sandwich. The sandwichwith the thin Mylar film up was exposed through a continuous tonephotographic negative in contact with the thin Mylar film to a 275 wattU.V. lamp positioned 9" away for 3 minutes. The sandwich was peeledapart and a negative image, i.e. one identical to the photographicnegative through which the light passed, adhered to the thick Mylarbottom film and a positive continuous tone image, i.e. reversed relativeto the negative through which the light passed, was formed on the thinclear Mylar. The positive image was immersed in an ultrasonic bathcontaining ethanol at 60 C. for 10 seconds to remove uncured polymer.Both images were then reexposed directly to the 275 watt U.V. lamp for30 seconds. The thus reexposed positive image was laminated to whitepigmented polyvinyl chloride with Qui'k Stick a commercially availablespray adhesive to give a silverless, black and white, continuous tone,photographic print of excellent quality.

EXAMPLE 24 27 g. of the triacrylate of the reaction product of one moleof trimethylol propane with 20 moles of ethylene oxide was admixed with9 g. of pentaerythritol tetrakis (B-mercaptopropionate). 1.5 g. ofbenzophenone was added to the mixture to form a photosensitivecomposition and mixing was continued for 2 minutes. The procedure ofExample 23 was repeated except that the photosensitive compositionprepared in this example was substituted for the photocurablecomposition used in Example 23. The visual appearance and quality of thephotocured polymer print obtained in this example was such that it couldnot be difierentiated from a standard silver halide print made from thesame negative using conventional printing technology. This exampleillustrates the use of a reactive ene group conjugated with anotherdouble bond grouping (C=).

EXAMPLE 25 50 g. of a liquid hydroxy terminated polybutadiene derivativehaving a molecular weight of about 2200 and a double bond distributionconsisting of about 60% trans- 1,4; and about 50% cis-1,4; and about 20%vinyl-1,2 (commercially available from Sinclair Petrochemical Inc. underthe trade name Poly B-D-R 45M"), g. of pentaerythritol tetrakis(B-mercaptopropionate) 7.5 g. of carbon black (Sterling FT) were mixedtogether in ethylene glycol monoethyl ether and heated in a vacuum ovenfor 5 minutes at 120 C. 5.0 g. of benzophenone were added to the mixtureand mixing was continued for 2 minutes. The procedure of Example 23 wasfollowed except that the photocurable composition herein was substitutedfor the photocurable composition employed in Example 23. The resultantphotocurable polymer print had the visual appearance and quality of astandard silver halide print made from the same negative usingconventional printing technology.

EXAMPLE 26 g. of a solid SBR Rubber commercially available from GeneralTire & Rubber Co. under the trade name Gentro 1002 was dissolved in 50g. of Decalin (as a solvent). 1 g. of pentaerythritol tetrakis(fi-mercaptopropionate), 0.1 g. of silica (Hi Sil 233) and 0.5 g. ofcarbon black along with 0.5 g. of benzophenone were then added to thesolution and mixing was continued for 3 minutes. The procedure ofExample 23 was repeated except that the photocurable composition made upherein was substituted for the photocurable composition used in Example23. The photocured polymer print obtained in the instant example wassuch that it could not be differentiat'ed from a standard halide printmade from the same negative using conventional printing technology.

EXAMPLE 27 39.8 g. of trimethylolpropane tris (fl-mercaptopropionate),20.1 g. of triallyl cyanurate, 3.0 g. of carbon black and 5.0 g. ofbenzophenone were admixed in the absence of U.V. light for 2 minutes.The procedure for forming a print of Example 23 was repeated except thatthe photocurable composition formed herein was substituted for thephotocurable composition used in Example 23. The silverless, black andwhite, continuous tone, photographic print had the same appearance andquality as that made from a standard silver halide print using the samenegative employing conventional silver technology. This exampleillustrates the use of a photocurable composition containing a monomericpolyene and a monomeric polythiol.

EXAMPLE 28 Example 23 was repeated except that the photocurablecomposition contained 50 g. of Polymer B from Example 22, "60 g. of thepolymeric polythiol used in Example 22, 9 g. of carbon black and 10.0 g.of benzophenone. The visual appearance and quality of the photocuredpolymer photographic print obtained in this example was such that itcould not be differentiated from a standard silver halide print usingconventional printing technology. This example illustrates the use of aphotocurable composition containing a polymeric polyene and a polymericpolythiol.

Conventional photography is restricted either to black and white imageswhich can, at most, be modified to give blue or brown tones or to fullcolor images in which the colors of the final print closely resemblethose of the subject matter. In the process described herein, there isno such restriction since, by the use of suitable dyes in thephotopolymer and colors in the support to which the image is laminated,any combination of colored images may be obtained in printing any givenphotographic negative.

The following example shows the versatility of the instant invention inobtaining prints of various colors other than the ordinary black andwhite print.

EXAMPLE 29 (1 0 g. of Polymer A, 0.9 g. of pentaerythritol tetrakis (,6-mercaptopropionate) and 1.5 g. phthalocyanine blue commerciallyavailable from Harshaw Chemical Co. in ethylene glycol monoethyl etherwere mixed together and then heated in a vacuum oven for 5 minutes at C.0.2 g. of benzophenone was added to the mixture and mixing was continuedfor 2 minutes. A 1 mil film of the photocurable mixture was spread on asheet of opaque Mylar and a sheet of clear Mylar was rolled on top ofthe photocurable mixture to produce a sandwich. The thus formedsandwich, clear side up, was exposed through a continuous tonephotographic negative in contact therewith to a 275 watt U.V. lampsituated 9" away for 3 min utes. The negative was removed and thesandwich was peeled apart, resulting in a positive image, i.e. onereverse to the photographic negative through which the light passedadhering to the clear Mylar while the residual material was left on theopaque Mylar. Uncured polymer was removed from the images by blottingwith paper soaped in ethanol. The positive, continuous tone image, i.e.reversed relative to the negative through which the light passed thusformed on the clear Mylar was then dried and laminated to a piece ofhigh reflectance yellow paper to give a silverless, green and yellow,continuous tone photographic print of excellent quality and appearance.

EXAMPLE 30 30 g. of Ricon 150, a polybutadiene of molecular weightapproximately 2000 containing 70% pendant vinyl groupings and sold bythe Richardson Co., Melrose Park, 111., was mixed with 65 g. ofpeutaerythritol tetrakis (13-.- mercaptopropionate), 8 g. ofbenzophenone and 3.2 g. of Sterling FT carbon black. A 1 mil layer ofthe resulting mixture was laminated between two sheets of clearpolyvinyl chloride film and exposed under a continuous tone negative for1 minute to a 4000 watt pulsed xenon arc lamp 2 feet away. The laminatewas stripped apart and the polyvinyl chloride adjacent to the negativewas rinsed with ethanol, dried, and laminated to a piece of highreflectance white paper. An excellent continuous tone positive print wasproduced.

The following example shows a method for producing a photographiccontinuous tone positive microfilm from a continuous tone negative whichdoes not use silver salts as the imaging medium.

EXAMPLE 31 26.4 g. of Polymer A, 1.82 g,. of pentaerythritol tetrakis(B-mercaptopropionate), 1.0 g. of carbon black (Sterling FT) and 2.0 g.of benzophenone were admixed in the absence of U.V. light for 10minutes. A 1 mil layer of this mixture was laminated between opaqueMylar and 0.005" thick clear Mylar :(silverless photographic paper). Thethus formed sandwich was exposed through its clear film side and througha microfilm as a negative to a 275 watt U.V. lamp positioned 9" away for/2 minute. The sandwich was peeled apart and the uncured polymer wasremoved from the positive image on the clear Mylar by immersing same inan ultrasonic bath containing ethanol at 60 C. for 10 seconds. Sinceattrition of the silverless emulsion would occur with use of the film, alayer of clear Polymer A was cast on top of the cured polymer image anda second layer of 0.005 clear Mylar was laminated to the thus formedmicrofilm.

EXAMPLE 32 The procedure of Example 3 was employed except that 10 g. ofthe reaction product of polytetramethyleneether glycol having amolecular weight of about 2,000 and alkyl isocyanate in a mole ratio of1:2 respectively were substituted for the 10 g. of Polymer A. Anexcellent quality silverless, black and white, continuous tonephotographic print resulted.

EXAMPLE 33 The procedure and reactants of Example 3 were employed exceptthat 10 g. of the reaction product of polyoxypropylene glycol sold underthe trade name NIAX by Union Carbide Co. having a molecular weight ofabout 2,000, tolylene 2,4-diisocyanate and allyl alcohol in a mole ratioof 1:2:2 respectively was substituted for the 10 g. of Polymer A. Theresultant continuous tone, black and white, silverless, photographicprint was of excellent quality.

EXAMPLE 34 The procedure and reactants of Example 3 were employed exceptthat 10 g. of the reaction product of a linear solid polyester diolhaving a molecular weight of about 3200 commercially available fromHooker Chemical C0. under the trade name Rucofiex 5-1011-35 and allylisocyanate in a mole ratio of 1:2 respectively was substituted for theg. of Polymer A. The resultant silverless continuous tone photographicprint was of excellent quality.

EXAMPLE 35 The procedure and reactants of Example 3 were employed exceptthat 10 g. of the reaction product of a phthalate esterol having amolecular weight of about 4200, hydroxyl number of 26.8, 1.22 diesterunits per mole and being commercially available from Quaker Oats Co.under the trade name Polymeg 2000 Phthalate Esterol and allyl isocyanatein a mole ratio of 1:2 respectively was substituted for the 10 g. ofPolymer A. The resultant silverless, black and white, continuous tone,photographic print had excellent quality.

EXAMPLE 3 6 The procedure and reactants of Example 23 were followedexcept that 31.6 g. of the reaction product of a polytetramethyleneetherglycol commercially available from Quaker Oats Co. having a hydroxylnumber of 37.1 and a molecular weight of about 3,000 and allylisocyanate in a mole ratio of 1:2 respectively was substituted for the25.6 g. of the reaction product of 1 mole of 1,4-butanediol with 2 molesof allyl isocyanate and 2.6 g. trimethylolpropane tris(fi-mercaptopropionate) was substituted for the 24.4 g. ofpentaerythritol tetrakis (B-mercaptopropionate). The resultantsilverless continuous tone photographic print was of excellent quality.

EXAMPLE 37 Example 23 was repeated except that 62.5 g. of the reactionproduct of a polypropylene glycol having a molecular weight of about6000 sold under the trade name Triol 6000 by Union Carbide Corp. andallyl isocyanate in a mole ratio of 1:3 respectively was substituted forthe 25.6 g. of the reaction product of 1 mole of 1,4-butanediol and 2moles of allyl isocyanate and 3.6 g. of ethylene glycol bis(B-mercaptopropionate) was substituted for the 24.4 g. ofpentaerythritol tetrakis (fl-mercaptopropionate). The resultantsilverless, continuous tone, black and white, photographic print hadexcellent quality.

EXAMPLE 3 8 Using conventional silver halide film, 3 separationnegatives were prepared by photographing an outdoor scene with a 4 x 5Calcumet View Camera, 6 /2" Ilex-Calumet Caltar f6.3 lens with thecamera mounted on a tripod. The negatives were prepared through thefollowing filters: Wratten #25 (red), Wratten #58 (green) and Wratten#47B (blue). The resulting black and white negatives were developedusing conventional silver photography methods.

The negative prepared through the red filter was printed using thereactants of Example 2 except that 1.5 g. of Adpro blue dye wassubstituted for the 1.5 g. of carbon black. The negative preparedthrough the green filter was printed using the reactants of Example 2except that 1.5 g. of Adpro yellow dye was substituted for the carbonblack. The negative prepared through the blue filter was printed usingthe reactants of Example 2 except that 1.5 g. of Adpro red dye wassubstituted for the carbon black.

For the printing, each negative was placed over its aforestatedphotosensitive composition of Example 2 sandwiched between a sheet ofopaque Mylar and a 1 mil thick sheet of clear Mylar on top in contactwith the negative. The sandwich, clear side up, was exposed through thenegative to a 275 watt U.V. lamp 9" away for 2%. minutes for thephotosensitive composition containing the blue dye, 3% minutes for thephotosensitive composition containing the red dye and 1 minute for thephotosensitive composition containing the yellow dye.

Each sandwich containing the photosensitized composition was then peeledapart and uncured polymer was removed by immersing the positive imagefor each negative in an ultrasonic bath containing ethanol for 10seconds. The images were then dried, laminated together in register andthereafter laminated to a white, opaque, reflectance paper to produce athree color silverless, photographic print.

The following example illustrates the use of the process of thisinvention to prepare a silverless photographic film useful in manycommercial graphic arts applications.

EXAMPLE 39 An original line image in black and white was photographedusing a process camera containing a silverless photographic filmcomprising the photosensitive composition of Example 18. The art workwas illuminated by reflection copy techniques according to establishedgraphic arts photographic procedures using the radiation from two 4000watt pulsed xenon arc printing lamps. The exposure time was 5 minutes.

Using essentially the procedure of Example 10, a silverless photographicnegative was obtained. The overall time for preparation of the negative(i.e. the combined exposure and development time) was less than 7minutes and no darkroom was required for this work.

The silverless photographic negative then was used successfully toprepare the following articles: (a) a letterpress printing plate (20mils image relief) and a litho graphic printing plate (0.5 mil imagerelief) according to the process described in co-pending application No.674,773 filed Oct. 12, 1967, (b) a photoengraving on metallic zinc usingconventional photoresists and the powderless etching technique (35 milsimage relief) as used by photoengravers in the preparation of engravingsfor conversion to fiexographic printing plates and (c) a conventionalsilk screen element which after exposure and washout was useful forprinting by the screen-process printing method.

The following example shows the ability of the instant invention to makeenlarged, silverless prints.

EXAMPLE 40 50 g. of Polymer A, 1.88 g. of carbon black (Sterling FT)4.55 g. of pentaerythritol tetrakis (B-mercaptopropionate) were mixedtogether and heated in a vacuum oven for minutes at 120 C. 5.0 g. ofbenzophenone was then added and mixing was continued for 2 minutes. A 1mil film of this photocurable material was spread on a sheet of opaqueMylar and a 1.0 mil thick sheet of clear Mylar was rolled on top of thematerial to produce a sandwich. The thus formed sandwich was positioned,clear side up, below a modified Beseler enlarger equipped with a 6"diameter Fresnel lens sz. f2 an f4.5 135 mm. Kodak enlarging Ektanonlens and a 275 watt U.V. lamp. A 35 mm. continuous tone negative wasplaced in the enlarger and the photocurable material was exposed throughthe negative to the U.V. lamp in a 3X enlargement for a time sufiicientto photocure the polymer. The sandwich was then peeled apart and thepositive, continuous tone image, adhering to the clear Mylar, wasimmersed in an ultrasonic bath containing ethanol at 60 C. for 10seconds to remove uncured polymer. The cured positive image was driedand laminated to a white pigmented polyvinylchloride sheet with acommercial spray adhesive Quik Stick to give a silverless, enlarged,black and white, continuous tone photographic print.

The following example shows the use of the instant invention to make aphotographic print and a negative simultaneously.

EXAMPLE 41 50 g. of Polymer A, 1.88 g. of carbon black (Sterling FT),4.55 g. of pentaerythritol tetrakis (fl-mercaptopropionate) were mixedtogether and heated in a vacuum oven for 5 minutes at 120 C. 5 g. ofbenzophenone was then added and mixing was continued for 2 minutes. 1mil layer of this photocurable material was spread on a sheet of clearMy1ar" (0.5 mil thick) and another 0.5 mil thick sheet of clear Mylarwas rolled on top of the material to produce a sandwich. The sandwichwas exposed through a conventional, continuous tone negative in contactwith one of the clear Mylar sheets to a 275 watt U.V. lamp positioned 9"away for 5 minutes. The sandwich was peeled apart and a negativecontinuous tone image, i.e. one identical to the negative through whichthe light passed adhered to the bottom Mylar sheet and a positivecontinuous tone image, i.e. reversed relative to the negative throughwhich the light passed, was formed on the top Mylar Sheet in contactwith the negative. The positive, image containing sheet was immersed inan ultrasonic bath containing ethanol at 60 C. for 10 seconds to removeuncured polymer. The negative image containing sheet was then reexposeddirectly to a 275 watt U.V. lamp for 30 seconds to further harden theimage. The positive image was dried and laminated to a sheet of whitepigmented polyvinyl chloride with Quik Stick a commercially availablespray adhesive to give a silverless, black and white, continuous tonephotographic print of excellent quality. The thus reexposed negativeimage was laminated to clear Mylar film with Quik Stick to give asilverless, continuous tone, photographic negative comparable to theconventional, silver halide-containing negative employed to make theprint in the instant example.

The following example shows the use of the instant invention to make ahalf-tone negative from a continuous tone photographic print.

EXAMPLE 42 10 g. of Polymer A, 0.9 g. of pentaerythritol tetrakis(,B-mercaptopropi'onate) and 1.5 g. of carbon black (Sterling FI') weremixed together and then heated in a vacuum oven for 5 minutes at 120 C.0.15 g. of dibenzosuberone was then added to the mixture and mixedtherein for 2 minutes. A 1.0 mil thick layer of this photosensitivematerial was spread on a film of opaque Mylar and a 1.0 mil thick filmof clear, U.V. transparent Mylar was rolled on top of the photosensitivelayer to produce a sandwich. The sandwich was put in a film holderbehind a Kodak contact screen containing 65 lines per inch. The filmholder was placed in a number 4 Xerox camera containing an 16 lens. Thecamera was focused on a continuous tone black and white print which wasilluminated with four 1,000 watt U.V. lamps. The film behind the screenwas exposed to the U.V. light reflected from the continuous tone printfor a period of 20 minutes. The film sandwich was removed from the filmholder, stripped apart and a latent negative half-tone image, i.e.reversed relative to the continuous tone positive print reflecting theU.V. light was formed on the clear Mylar along with uncured polymer. Todevelop the image, uncured polymer was removed from the thus formednegative by immersing said negative in an ultrasonic bath containingethanol at 60 C. for 10 seconds.

The thus formed silverless photographic negative was then usedsuccessfully to prepare the following articles:

(a) A letterpress printing plate (20 mil image relief) and alithographic printing plate (0.5 mil image relief) according to theprocess described in a copending application No. 674,773 filed Oct. 12,1967.

(b) A photoengraving on metallic zinc using conventional photoresistsand the powderless etching technique (35 mils image relief) as used byphotoengravers in the preparation of engravings for conversion tofiexographic printing prints, and

(c) A conventional silk screen element which after exposure and washoutwas useful for printing by the screen-process printing method.

The following example shows the use of the instant invention to form anunpigmented image which can thereafter be selectively dyed in theinsolubilized portion of the photosensitized composition to give acontinuous tone gradation.

EXAMPLE 43 10 g. of Polymer A, and 0.9 g. of pentaerythritol tetrakis(B-mercaptopropionate) were admixed together and then heated in a vacuumoven for 5 minutes at C. 0.15 g. of benzophenone was added to themixture and mixing was continued for 2 minutes. A 1 mil layer of thismaterial was spread on a film of opaque Mylar and a 1 mil thick film ofclear Mylar was rolled on top of the photosensitive layer to produce asandwich. The sand wich (clear side up) was exposed through a continuoustone negative to a 275 watt U.V. lamp 9" away for 3 minutes. Uponpeeling the sandwich apart, a latent positive continuous tone image,i.e. reversed relative to the negative through which the light passedwas formed on the clear Mylar. Uncured polymer was removed from thepositive continuous tone image by immersing same in an untrasonic bathcontaining ethanol at 60 C. for 10 seconds. The image was dyed byimmersing it in a bath of a solution of Nigrogine SSB dissolved indibutyl cellosolve for 15 minutes.

EXAMPLE 44 Example 39 was repeated except a half-tone print wasphotographed to give a half-tone negative.

What is claimed is:

1. A process for forming a silverless, continuous tone photographicimage having a gamma of 0.5 to 1.5 which comprises sandwiching a layeradjusted to a uniform thickness in the range 0.1 to 50 mils of acomposition comprising a uniform mixture of (1) a liquid photosensitivematerial having a viscosity in the range 0-20 million centipoises at 700, consisting essentially of a polyene containing at least two reactiveunsaturated carbon to carbon bonds per molecule and a polythiolcontaining at least two thiol groups per molecule, the total combinedfunctionality of the reactive unsaturated carbon to carbon bonds permolecule in the polyene and the thiol groups per molecule in thepolythiol being greater than 4, (2) 0.0005 to 33% by weight of saidcomposition of a photosensitizer and (3) a member of the groupconsisting of l-25% by weight of said composition of a pigment and 0.1to 25% by weight of a dye, between two support films at least one ofwhich is transparent to actinic radiation, exposing said composition toactinic radiation through its transparent support film and through animage-bearing continuous tone transparency, thereby causing portions ofthe composition exposed to actinic radiation to form a solidifiedreverse image relative to said transparency which adheres to the supportfilm proximate the actinic radiation source, stripping said supportfilms apart and re-exposing the unexposed portion of said composition onthe film support away from the actinic radiation source directly toactinic radiation, thereby forming two continuous tone images, one beinga positive and the other a negative.

2. The process according to claim 1 wherein said reverse image on thetransparent support is thereafter lami nated to a substantiallynon-transparent background material to give a continuous tonephotographic print.

3. The process according to claim 2 wherein the background material iswhite.

4. The process according to claim 1 wherein the continuous tone image onthe transparent support film is laminated to a transparent backgroundmaterial to give a continuous tone photographic transparency.

5. The process according to claim 1 wherein the composition contains inaddition a member of the group consisting of a plasticizer, a filler, anodor mask, a lightscattering agent and an antioxidant in an amount equalto 0.005 to 500 parts per 100 parts of the photosensitive composition.

6. The process according to claim 1 wherein the photosensitizer is amember of the group consisting of benzophenone, acetophenone,acenapthene-quinone, methyl ethyl ketone, valerophenone, hexanophenone,'yphenylbutyrophenone, p-morpholinoprpi0phenone, dibenzosuberone,4-morpholinobenzophenone, 4'-morpholinodeoxybenzoin, p-diacetylbenzene,4-aminobenzophenone, 4-methoxyacetophenone, benzaldehyde, a-tetralone,9- acetylphenanthrene, 2-acetylphenanthrene, l-thioxanthenone,3-acetylphenanthrene, B-acetylindole, 9-fiuorenone, l indanone, 1,3,5triacetylbenzene, thioxanthen-9-one, xanthrene-9-one,7H-benz[de]anthracene-7-one, il-naphthaldehyde, 4,4-bis(dimethylamino)benzoph'enone, fluorene-9-one, 1'-acetonaphthone, 2' acetonaphthone,2,3- butanedione, tert.-butyl anthraq-uinone, benzoin, benzoin methylether and mixtures thereof.

7. A process for forming a silverless, continuous tone photographicimage having a gamma of 0.5 to 1.5 in a camera which comprisessandwiching a layer adjusted to a uniform thickness in the range 0.1 to50 mils of a composition comprising a uniform mixture of (1) a liquidphotosensitive material having a viscosity in the range 0-20 millioncentipoises at 70 C., consisting essentially of a polyene containing atleast two reactive unsaturated carbon to carbon bonds per molecule and apolythiol containing at least two thiol groups per molecule, the totalcombined functionality of the reactive unsaturated carbon to carbonbonds per molecule in the polyene and the thiol groups per molecule inthe polythiol being greater than 4, (2) 0.0005 to 33% by weight of saidcomposition of a photosensitizer and (3) a member of the groupconsisting of l-25% by weight of said composition of a pigment and 0.1to 25% by weight of a dye, between two support films at least one ofwhich is transparent to actinic radiation, inserting the thus formedsandwich in a camera with a transparent support layer proximate theaperture and/or lens system, exposing said composition to actinicradiation reflected from a continuous tone scene onto said compositionthereby causing portions of the composition exposed to actinic radiationto form a solidified reverse image relative to said scene which adheresto the support film proximate the actinic radiation source, strippingsaid support films apart and re-exposing the unexposed portion of saidcomposition on the film support away from the actinic radiation sourcedirectly to actinic radiation, thereby forming two continuous toneimages, one being a positive and the other a negative.

8. The process according to claim 7 wherein said reverse image on thetransparent support is thereafter laminated to a substantiallynon-transparent background material to give a continuous tonephotographic print.

9. The process according to claim 8 wherein the background material iswhite.

10. The process according to claim 7 wherein the continuous tone imageon the transparent support film is laminated to a transparent backgroundmaterial to give a continuous tone photographic transparency.

11. The process according to claim 7 wherein the composition contains inaddition a member of the group consisting of a plasticizer, a filler, anodor mask, a lightscattering agent and an antioxidant in an amount equalto 0.005 to 500 parts per parts of the photosensitive composition.

12. A process for forming a silverless, line photographic image in acamera which comprises sandwiching a layer adjusted to a uniformthickness in the range 0.1 to 50 mils of a composition comprising auniform mixture of (1) a liquid photosensitive material having aviscosity in the range 0-20 million centipoises at 70 C., consistingessentially of a polyene containing at least two reactive unsaturatedcarbon to carbon bonds per molecule and a polythiol containing at leasttwo thiol groups per molecule, the total combined functionality of thereactive unsaturated carbon to carbon bonds per molecule in the polyeneand the thiol groups per molecule in the polythiol being greater than 4,(2) 0.0005 to 33% by weight of said composition of a photosensitizer and(3) a member of the group consisting of 1-25% by weight of saidcomposition of a pigment and 0.1 to 25% by weight of a dye, between twosupport films at least one of which is transparent to actinic radiation,inserting the thus formed sandwich in a camera with a transparentsupport layer proximate the aperture and/or lens system, exposing saidcomposition to actinic radiation reflected from art copy comprising aline image onto said composition thereby causing portions of thecomposition exposed to actinic radiation to form a solidified reverseimage relative to said transparency which adheres to the support filmproximate the actinic radiation source, stripping said support filmsapart and re-exposing the unexposed portion of said composition on thefilm support away from the actinic radiation source directly to actinicradiation, thereby forming two line images, one being a positive and theother a negative.

13. The process according to claim 12 wherein said reverse image on thetransparent support is thereafter laminated to a substantiallynon-transparent background material to give a line photographic print.

14. The process according to claim 13 wherein the background material iswhite.

15. The process according to claim 12 wherein the reverse image on thetransparent support film is laminated to a transparent backgroundmaterial to give a line transparency.

16. The process according to claim 12 wherein the composition containsin addition a member of the group consisting of a plasticizer, a filler,an odor mask, a lightscattering agent and an antioxidant in an amountequal to 0.005 to 500 parts per 100 parts of the photosensitivecomposition.

17. The process according to claim 12 wherein the photosensitizer is amember of the group consisting of benzophenone, acetophenone,acenapthene-quinone, methyl ethyl ketone, valerophenone, hexanophenone,-phenylbutyrophenone, p-morpholinopropiophenone, dibenzosuberone,4-morph01in0benzophenone, 4'-morpho1inode0xybenzoin, p-diacetylbenzene,4-aminobenzophenone, 4'- methoxyacetophenone, benzaldehyde, a-tetralone,9-acetylphenanthrene, Z-acetylphenanthrene, l-thioxanthenone, 3-acetylphenanthrene, 3-acety1indo1e, 9-fluorenone, l-indanone,1,3,5-triacety1benzene, thioxanthen-9-one, xanthrene-9-one,7-H-benz[de]anthracene-7-one, l-naphthaldehyde,4,4'-bis(dimethylarnino)benzophenone, flu0rene- 9-one,1'-acet0naphthone, 2-acetonaphthone, 2,3-butanedione, terL-butylanthraquinone, benzoin, benzoin methyl ether and mixtures thereof.

References Cited UNITED STATES PATENTS 3,615,435 10/1971 Chu 9635.1 X3,591,377 7/1971 Alsup 96-35.! 3,615,450 10/1971 Weber 9635.1

NORMAN G. TORCHIN, Primary Examiner J. L. GOODROW, Assistant ExaminerUS. Cl. X.R. 96115 P

